id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
23249	Filter Performance Issue	mrgenie	team	"I searched her for existing tickets concerning the filter performance but couldn't find any.

The thing is - when I enable a filter it's being applied in a certain amount of time. Quite acceptable I may add.

Now if I download my city - and apply a filter to only show road infrastructure and filter out everything else that takes let's say 2s to be applied.

And up to this point it's all just working very well.

Now the thing is - if I move a node, I click it and I move it to the new location, it's (out of my belly) exactly the same time as applying the filter again that's how long the JOSM hangs and is stuck before it moves that single node.

And this is with every action I perform, every single action the JOSM is stuck (again out of my belly) exactly the same time it takes to apply the filter.

So my guess is - every time any action is being performed with the filter active - the filter is doing the filtering again.

I think this is something that can be improved. Instead of having the filtering mechanism applied time and again - by not changing tags but just moving a tag - the filter mechanism shouldn't be re-applied if no tag values are added/deleted/changed.

I get it that the filter is being re-applied when a tag is being added/deleted/changed value for the key, etc.

but just moving a node, not changing anything else? Why apply the filter again and again for every single move?


And my second idea where we could improve the filtering technique.. create a bounding box around the area where actually changes are - and re-apply the filter not over all downloadeded data but only inside the bounding box where a change to the tag/value actually did occur.

I mean if I already filtered everything for all downloaded area.. and make a change only in like 1% of the downloaded area - I don't need to reapply the filter for the 100% of the downloaded area, only that small 1% it needs to be re-applied right.

So I think here is some significant PERFORMANCE INCREASE possible if someone of the programming team could optimize the filtering algorithms.

Thank you"	enhancement	closed	major		Core		worksforme